1. Field of Invention
The present invention relates to a color adjustment method and device for a multimedia apparatus, and more particularly, to a color adjustment method and device for providing gamut mapping non-linear adjustment and/or independent color non-linear adjustment.
2. Description of Related Art
The color adjustment for current multimedia apparatuses (such as display devices, TV sets, digital cameras, digital video cameras) includes gamut mapping and user preferred color adjustment. The so-called gamut mapping includes reducing or increasing the saturation of red and green colors, or moving the hue-chroma of the yellow color. The user preferred color adjustment indicates separately adjusting an independent color such as the color of grass, sky, and skin, without affecting other colors.
Restricted by the overall hue, saturation and brightness adjustments, a common display cannot provide the color adjustment of an individual hue. Some high-level displays provide advanced six-axial hue adjustment and brightness (gamma) adjustment, and enhance the adjustment of a specific independent color.
Taking the current color adjustment technology as an example, the RGB (red, green, blue) color information in the image is transformed into RGBCMY (red, green, blue, cyan, magenta, yellow) six-color information. Then, the saturation/intensity adjustment is performed through a six-color lookup table and a color control circuit. Finally, the result is transformed into a YCbCr signal to be outputted. The six-color lookup table is established based upon the relationship between an original image and an adjusted target image.
Furthermore, in another conventional art, the RGB color space is transformed into a CIELab color space, and then transformed into lightness-chroma-hue (LCH) color space. Then, the default user preferred color is obtained by performing a continuous and smooth chroma transformation within a default color range. However, the disadvantage lies in that the hardware architecture is complicated and high cost.
However, the above current technology cannot provide an optimal and consistent output result. Furthermore, the current color adjustment cannot provide independent color non-linear adjustment.